1. Field of the Invention
The present invention relates to systems and methods for milling paving material. More particularly, the present invention relates to systems and methods that provide increased stability, support and power while grinding paving material.
2. Background of the Invention and Related Art
Asphalt milling is a technique currently employed to remove asphalt pavement for reconstruction or resurfacing, and for accessing buried utility lines. The technique involves the removal of asphalt pavement through the use of a cold planer, which can remove up to approximately two inches of pavement surface during a particular pass.
A cold planer typically includes a barrel-like attachment, referred to as a mandrel, and a variety of bits that are affixed to the exterior surface of the mandrel. Coupled to the cold planer is a vehicle (e.g., a bobcat or skid-steer) that is used to propel the cold planer. The mandrel rotates and is pushed into the pavement by the hydraulic system of the vehicle, causing the bits to grind up the asphalt pavement. The vehicle pushes the cold planer as the mandrel rotates to grind a trench in the asphalt pavement that is typically up to 24 inches wide.
While this technique enables the creation of a trench that is up to 2 inches deep, various problems exist. For example, traditional cold planers stall out upon attempting to grind 2–3 inches of asphalt pavement. Thus, when desiring to mill a depth of 6 inches of pavement, at least three passes of the cold planer must be conducted. Furthermore, the milled asphalt composite left behind in the wake of the cold planer must be removed between each pass. As a result, this process has proven to be time consuming.
The process is further delayed by the requirement of having to push the cold planer at an extremely slow rate. Much of the power from the skid-steer is used to rotate the mandrel. As such, limited power is available to push the cold planer forward. Typically, the cold planer creates a trench by grinding the pavement at a rate of up to ½ mph.
The process is further hampered by instability. The vehicle used to propel the cold planer typically loses traction and has a tendency to shake. A loss in pressure between the actions of providing pressure on the cold planer and lowering the mandrel also yields to instability. Moreover, a procedure of edge milling typically requires the removal of supporting structures of the cold planer, triggering further instability.
Thus, while the traditional technique of asphalt milling enables the creation of a milled trench that is up to 2 inches deep, the technique has proven to be instable and time consuming. Accordingly, it would be an improvement in the art to augment or even replace existing techniques to enable a trench to be milled in asphalt pavement at a quicker rate and/or to provide increased stability to the milling process.